Are Your Tree Leaves Already Brown? Anthracnose May Be the Cause

Posted on Oct 8 2018 - 4:50pm by Johnny B

You want to look out to your yard and see the beautiful lush trees that you’ve planted. However, if you see that your leaves and bushes are turning brown when they should still be a deep green, anthracnose may be the cause.

Anthracnose is a fungal disease of plants causing parts of leaves, branches, fruit, and vegetables to develop dark lesions. In the Pacific Northwest where trees are in abundance, trained professionals, such as arborists in Portland, Oregon, will know how to treat this disease and prevent it from returning to the affected area.

If you see brown spots on your leaves, this is what you should know:

What is Anthracnose? 

Anthracnose is a term that specifically refers to a particular set of symptoms caused by fungi. When plants are infected, a dark water-soaked lesion appears on the stem or fruit. Be careful, because it only takes a few days for an infected tree to go from thriving to a state of decay.

Anthracnose occurs because of a large amount of stress placed on the tree. It may develop because it’s in a high volume traffic area, from poor nutrients, limited water availability, and from mowing too closely to the base of the tree. If the cause of stress is not removed, you will likely see this pathogen constantly returning to the same areas of your property.

How to Identify Anthracnose

Once anthracnose is identified it should be treated right away.

This pathogen tends to attack plants in the spring when the weather is warm or humid and it primarily occurs on leaves and twigs. In the early stages, you may also notice yellowing of the grass. In time, the spotting will take over the whole tree. On leaves, the dark spots develop to be about 1 to 5 millimeters in diameter. You can also find these small sightings on vegetables and fruit.

Young leaves that are infected or branches that grow in an infected area will deform and twist. Leaves that are heavily infected will fall prematurely, which can lead to complete defoliation. If this occurs, it is likely that new leaves will grow back. However, you will want to make sure your local tree professional takes a look at the issue to make sure that the disease is completely removed from the area.

The lesions will continue to develop if not treated. However, if the plant is strong and healthy, it can survive and fight this pathogen.

How to Manage Anthracnose 

Treating this disease begins with good sanitation. Do not rake fallen infected leaves and make sure to dispose of the infected twigs, leaves, and branches. Removing the debris around the plant is important because it keeps the fungus from spreading. Do not use infected leaves or stems as compost as this will only spread the disease. 

You may want to have trained arborists in Portland, Oregon properly maintain your yard to treat the disease or prevent anthracnose from reaching your space. With diligent tree management, plants that were once infected can still have a chance to thrive.

However, If you are going to plant new trees in the area, choose ones that are more resistant to the fungi. Try to use western-grown seeds as they are less likely to have been infected.

Environmental factors also play an important role in treating an anthracnose breakout. Increase the sunlight and air circulation to help manage the disease, provide trees with enough space when planting, and make sure to prune them during the winter as the cold and rainy seasons are the ideal times for anthracnose to spread.

There are some cultural methods of control to help treat the pathogen as well. The main goal is to reduce the amount of physical stress to the tree. Besides taking quick yard sanitation measures, put down some mulch. Just make sure that the mulch doesn’t sit immediately next to the base of the tree. This step will prevent anthracnose spores from moving from surrounding plants and soil into the tree.

Chemical treatment is not favored, but is also an option. Some chemicals that provide both preventative and treatment action include Instrata, Chipco Green, and Heritage Maxx. Regularly change up the the active ingredients to avoid pathogen resistance and be careful of using these products around children and pets.

If you want an organic option, sulfate, neem oil, and Serenade Garden may also be effective.

Unfortunately, once the disease is severe, it can’t be controlled during the growing season.

How to Prevent Anthracnose 

Even after this pathogen is gone from your yard, there is no guarantee that it won’t return. Keep your yard free of debris and alter the yard’s overall environment after the anthracnose is removed. Cold weather and high rainfall instigates the pathogen, so those in the Pacific Northwest should be more weary of these weather triggers.

As a reminder, take the following steps:

  • Purchase disease-free planting material from a reliable and reputable nursery.
  • Keep trees healthy by providing the proper amount of sunlight and air.
  • Make sure to have regular care performed by a professional to keep your yard healthy and maintained.
  • Prune regularly and wash your hands and tools when pruning between cuts to prevent any opportunities of spreading the pathogen.
  • Keep the yard fertilized and improve soil quality to create a healthy space that can fight this pathogen if it appears.

If you see any anthracnose symptoms, act immediately before it spreads. Brown spots on your tree are never normal, so don’t hesitate. Reach out to arborists in Portland, Oregon today.